LTC7893/LTC7892: 100V Low IQ, Synchronous Boost Controllers for GaN FETs
The LTC7893/LTC7892 are high-performance, step-up DC-to-DC switching regulator controllers that drive all N-channel synchronous gallium nitride (GaN) field-effect transistor (FET) power stages from output voltages of up to 100V.
The LTC7893/LTC7892 solves many of the challenges traditionally faced when using GaN FETs. It simplifies the application design while requiring no protection diodes and no other additional external components compared to a silicon metal-oxide-semiconductor field effect transistor (MOSFET) solution.
The Internal smart bootstrap switches prevent overcharging of the BOOSTx pin to the SWx pin the high-side driver supplies during dead times, protecting the gate of the top GaN FET. The dead times of the LTC7893/LTC7892 can optionally be optimized with external resistors for margin or to tailor the application for higher efficiency and allowing for high-frequency operation.
The gate drive voltage of the LTC7893/LTC7892 can be precisely adjusted from 4V to 5.5V to optimize performance and allow the use of different GaN FETs or even logic-level MOSFETs. When biased from the boost converter regulator output, the LTC7893/LTC7892 can operate from an input supply as low as 1V after start-up.
Key Features and Benefits
- GaN Drive Technology fully Optimized for GaN FETs
- Output Voltage up to 100V
- Wide VIN Range: 4V to 60V and Operates Down to 1V After Start-Up
- No Catch, Clamp, or Bootstrap Diodes Needed
- Internal Smart Bootstrap Switches Prevent Overcharging of High-Side Driver Supplies
- Resistor Adjustable Dead Times
- Split Output Gate Drivers for Adjustable Turn-On and Turn-Off Driver Strengths
- Accurate Adjustable Driver Voltage and UVLO
- Low Operating IQ: 15μA
- Programmable Frequency (100kHz to 3MHz)
- Synchronizable Frequency (100kHz to 3MHz)
- Spread Spectrum Frequency Modulation
- 28-Lead (4mm × 5mm), Side Wettable, QFN Package (LTC7893)
- 40-Lead (6mm × 6mm), Side Wettable, QFN Package (LTC7892)
- AEC-Q100 Qualified for Automotive Applications
Applications
- Automotive and Industrial Power Systems
- Military Avionics and Medical Systems
- Telecommunications Power Systems
Evaluation Board
The LTC7893/LTC7892 can be evaluated with the EVAL-LTC7893-AZ and the EVAL-LTC7892-BZ, respectively.
Block Diagrams and Tables
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